Conventional devices which are used to perform very complex and/or physically demanding surgical procedures like neurosurgery, spine surgery, ear surgery, head and neck surgery, hand surgery and minimally invasive surgical procedures have a number of drawbacks as it relates to the dexterity of the surgeon. For example, the surgeon can easily become fatigued by the need to manually support the surgical device during its use. Additionally, the surgeon may have to orient his hands in an awkward position in order to operate the device. Furthermore, conventional devices used in such surgical procedures can produce angular magnification of errors. As a result, a surgeon has considerably less dexterity and precision when performing an operation with such surgical devices than when performing an operation by traditional techniques in which the surgeon grasps a tool directly.
Accordingly, there is an increasing interest in the use of powered manipulators, such as robotic and master-slave manipulators for supporting and manipulating surgical tools during medical procedures. Such manipulators can provide a number of advantages to both patients and medical practitioners. In particular, a master/slave controlled manipulator can enhance the dexterity of the surgeon/operator so as to allow the surgeon to manipulate a medical tool with greater dexterity than he could if he was actually holding the tool in his hands. A manipulator can also reduce the fatigue experienced by a surgeon, since it eliminates the need for the surgeon to physically support the medical tool or device during its use. Additionally, the surgeon can let go of the manipulator and perform other tasks without the medical tool undergoing movement, which increases the efficiency of the surgeon and can reduce the number of individuals that are necessary to perform a particular procedure. Thus, manipulators can allow medical procedures to be performed much more rapidly, resulting in less stress on the patient.
However, the use of such powered manipulators can impose certain safety problems. In particular, movement of the patient relative to the manipulator during the surgical or other interventional procedure can lead to serious trauma. Thus, it is generally thought that a patient must be under a general anesthesia or other paralytic during a procedure that is performed using a powered manipulator. Powered manipulators are generally thought as unsuitable for use in awake procedures. The use of a general anesthesia including neuro-muscular paralysis or the like, however, introduces more risk into the procedure and does not completely solve the problem of movement of the patient relative to the manipulator. For example, even when under a general anesthesia patient motion can be caused by respiration, cardio-ballistic motion, involuntary muscle motion (e.g., myoclonic jerks, tremors, twitching), peristalsis and inadvertent contact with the patient.